Hello.

I were asked to consider the following from our PM today.

The fluid weight of the pipe connected to the pump top nozzle is supported in the pump foundation, therefore no additional spring supports are required.

Generally, fluid weight is necessary to design a spring support
I'm so confused

Thanks.

Its true!!

The liquid column weight will go via nozzle to pump base.

But if you have a reducer on the nozzle, maybe...

Generally, springs are added to protect against thermal expansion of the pipe redistributing the loads off pipe supports and onto the pump nozzle.

Adding a spring to take the load off a pump nozzle due to weight alone strikes me as improper design, as this is quite literally "cold spring."

But I disagree with your PM. He's only considering the static load.

Here's a thought experiment for you:
You have an incredibly long vertical span of pipe. It is fluid packed. The top is blinded off - i.e. no fluid is being added. Ignore time. Ignore velocities. You're at time 0.

Gravity wants to remove the fluid from your system. You innately understand that fluid is not going to just slide out of the pipe as though it doesn't exist. This is because a vacuum attempts to form at the top... and all the way throughout the system... and gases have to come up from the bottom, and it's going to "glug-glug-glug" until it's empty.

Yes, in a static world, your fluid load is held up exclusively by upward-facing forces.

What's holding up the fluid? The air at the bottom? No. The pipe.

Once you start adding motion to the system, we get confused and tell ourselves there is no vacuum. But it's there.

Paek,

You may start from the following fact: Pump's Manufacturer has to consider the effect of pressure (that normally is counted as weight of liquid column) that acts on the impeller and transmitted via bearings/ stuffing box to casing, baseplate and foundation. This is about how pressure is developed in a centrifugal pump. You may say that the impeller is the "bottom" of the liquid column.
For your case, you must analyze different scenarios in operation- for example is there, on your vertical pipe, a "device"- a spectacle blind or a valve that could be the "bottom" of a liquid column? In this case the load of column is transmitted to pipe, nozzle, casing, baseplate and foundation.